Isaiah 55 tells us about God's gift of salvation, given freely out of grace, to be received through faith. For His way is higher than our way, and the physical and emotional satisfaction that one attains from money and labour cannot compare to the spiritual satisfaction that one gets from following Jesus.
55:1 “Come, all you who are thirsty, come to the waters; and you who have no money, come, buy and eat! Come, buy wine and milk without money and without cost.
55:2 Why spend money on what is not bread, and your labor on what does not satisfy? Listen, listen to me, and eat what is good, and your soul will delight in the richest of fare.